The present invention relates to aircraft manufacturing systems and methods. In particular, but not by way of limitation, the present invention relates to systems and methods for shifting, or repositioning, an aircraft fuselage on a wing during aircraft development or manufacture to adjust the center of gravity (CG) location of a resulting aircraft.
In the avionics field, proper positioning of the center of gravity (CG) of an aircraft is essential. For example, if the CG of an aircraft is positioned too far forward of the aerodynamic center of the wing, a pilot can experience significant difficulty in attempting to control the aircraft during flight. Similarly, if the CG of the aircraft is positioned to far aft of the aerodynamic center of the wing, the aircraft will become inherently unstable.
Stated somewhat differently, in order to maintain proper stability of an aircraft, the CG should not under any condition of fuel loading, passenger loading, cargo loading, or any other type of loading be positioned rearward of a rear stability limit. And, in order to maintain proper control, for example, during take offs and landings, the CG should never be positioned forward of the aerodynamic limit of the aircraft.
One, thus, can readily understand that, when design criteria are altered for an aircraft, such as when a different passenger seating configuration is selected or a different propulsion system is selected, it can become necessary to shift, or reposition, the fuselage of an aircraft on its wing. And, where conventional aircraft manufacturing systems and techniques are employed, this can result in a complete redesign of the aircraft and the tools used to build or assemble it.
Those skilled in the art of aircraft manufacture and design will appreciate, therefore, that a need exists for an improved method of repositioning a fuselage on a wing, when significant design changes are encountered in an aircraft development process.
Exemplary embodiments of the present invention that are shown in the drawings are summarized below. These and other embodiments are more fully described in the Detailed Description section. It is to be understood, however, that there is no intention to limit the invention to the forms described in this Summary of the Invention or in the Detailed Description. One skilled in the art can recognize that there are numerous modifications, equivalents and alternative constructions that fall within the spirit and scope of the invention as expressed in the claims.
In one particularly innovative aspect, the present invention is directed to systems and methods for adjusting the location of the CG of an aircraft by shifting, or repositioning, the fuselage of an aircraft on its wing without requiring a complete retooling of the fuselage and wing assembly.
In one presently preferred embodiment, a modular spar tunnel is provided within a mold for constructing a fuselage section of an aircraft. The modular spar tunnel is configured to engage, or be mounted within, a main mold for a portion (typically the right or left side) of the fuselage of the aircraft. In this fashion, the spar tunnel of an aircraft can be shifted forward or rearward within a fuselage section of an aircraft without a major retooling operation, and without modifying other elements or aspects of the aircraft. Thus, if a different propulsion system is selected for an aircraft design, major retooling of the molds used to manufacture the aircraft may not be required.
In another innovative aspect, the present invention is directed to a method for assembling a fuselage of an aircraft using a multi-component molding and composite manufacturing process. A modular spar tunnel of the type described above is utilized to locate a spar tunnel within a fuselage of an aircraft, and layers of composite fiber are laid up within the mold, and thereafter cured, to form a portion of the fuselage of the aircraft. Using methods in accordance with the present invention, it is possible to accommodate significant design variations between aircraft without engaging in a major retooling process and incurring the costs associated with such retooling.
As previously stated, the above-described embodiments and implementations are for illustration purposes only. Numerous other embodiments, implementations, and details of the invention are easily recognized by those of skill in the art from the following descriptions and claims.